Brass will work...but mold release will be important...hot lead WILL bond to hot brass surprisingly well... if given an opportunity. Smoking the mold with a sulphur match might work...this is how the old cast iron molds were prepped. There are also commercially available release compounds that might work.

Vents should be spaced about every 3mm of the projectile height. Don't need to be deep, .005"-.010" has proven adequate. Make them on both sides of the cavity.

I suspect Jake CAN indeed get it hot enough.

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